Hello!
Is he your RL friend? and how does he take criticism?
If he's your RL friend and he doesn't take criticism well, don't bother. Simply refer him to someone else that isn't you. Not worth the hassle
You can start by letting him to bookmark the following websites
www.lolcounter.com (easy way for him to learn what champions counter eachother)
www.probuilds.com (runes & masteries + possible Build path)
www.lolking.com (look at his stats/performance chart and see what needs work)
www.lolnexus.com (see the runes & masteries of his opponent)
See if you can get him to watch certain "educational league streams"
http://www.twitch.tv/scarra
The advice you can give him is that A) he needs to man up and grow a pair. B) Never blame his team and don't look for their faults
This game becomes a lot easier when people start to realize that criticizing and watching the faults other people make do not help you. the 0-6 Jungler who according to you is ruining your game is going to be someone else's problem next game.
Learn from your own mistakes, be harsh on yourself when you fuck up or when you didn't push your advantage to the maximum.
Best of luck!